ICD-10 Code for History of Kidney Stones
The ICD-10 code for personal history of kidney stones (urolithiasis/nephrolithiasis) is Z87.442.
This code falls under the category of "Personal history of other diseases of the urinary system" and is specifically designated for patients who have previously had kidney stones but do not currently have active stone disease.
Key Coding Considerations
When to Use Z87.442
- Use this code when documenting a resolved history of kidney stones in patients who are stone-free at the time of the encounter but have had stones in the past 1.
- This code is appropriate for patients being evaluated for recurrence risk, as approximately 50% of recurrent stone-formers experience at least one recurrence, with 26% recurring within 5 years of their first stone 1, 2.
- The code should be used when the history of stones is relevant to current clinical decision-making, such as when implementing preventive strategies or monitoring for new stone formation 2.
When NOT to Use Z87.442
- Do not use this code if the patient currently has active kidney stones—instead use the appropriate active disease codes (N20.0 for kidney stones, N20.1 for ureteral stones, N20.2 for kidney stones with ureteral stones) 1, 3.
- If a patient passes a pre-existing stone after implementing dietary changes, this represents passage of an old stone, not treatment failure, and the active stone code should be used until the stone is confirmed passed 2.
Clinical Context for Documentation
Risk Stratification Matters
- Document whether the patient had a single distant episode (>10 years ago) versus recurrent disease, as this affects clinical management and follow-up intensity 1.
- Patients with a distant history of a single stone more than 10 years ago without recurrence are considered lower risk 1.
- The risk of a second stone is 50% within 5-7 years after the first stone diagnosis, making accurate historical documentation critical 1.
Supporting Documentation
- Include stone composition if known (calcium oxalate, uric acid, struvite, cystine), as this guides preventive therapy and may require additional ICD-10 codes for underlying metabolic conditions 1, 3.
- Document any metabolic abnormalities identified during workup (hypercalciuria, hyperoxaluria, hypocitraturia) with their respective codes, as these affect long-term management 2, 4.
- Note any genetic testing results if performed, particularly in patients with early-onset disease (≤25 years), as 12-21% of young adults have monogenic forms requiring specific coding 1, 4.
Common Pitfalls to Avoid
Coding Accuracy Issues
- ICD codes for kidney disease have historically shown variable accuracy, with studies demonstrating that while specificity is high (>95%), sensitivity can be low, particularly for disease staging 5, 6.
- Ensure the history code Z87.442 is not confused with active disease codes (N20.x series), as this distinction is critical for accurate epidemiological tracking and clinical decision-making 5, 7.
Clinical Documentation
- Always document the timeframe of the last stone episode and whether imaging confirmed complete stone clearance, as this affects whether Z87.442 or an active disease code is appropriate 3.
- Include relevant comorbidities (obesity, diabetes, hypertension, metabolic syndrome) with their own ICD-10 codes, as these are commonly associated with stone disease and affect recurrence risk 2, 4.